This invention relates to mechanism for trimming the inserted leads of components mounted in preformed holes of circuit boards, or the like, and then bending the cut leads to effect their electrical connection, usually to the printed circuitry on the boards.
As components to be mounted on circuit boards by lead insertion have become smaller and more densely arranged, it has become desirable to provide more versatile and more compact cut-clinch mechanisms for suitably trimming the leads and directing the cut leads for reliable electric connection to the printed circuitry on the boards. In U.S. Pat. No. 3,429,170 to Romeo, for instance, there is disclosed a pair of cut-clinch mechanisms rotatable about an axis normal to the circuit board to orient the mechanisms according to the position of the leads extending through the board. Such an arrangement has found wide usage but lacks capability to handle different lead or "leg" spacings, i.e. the distance (which may vary) between the centers of preformed lead-receiving holes in the board. Other cut-clinch mechanisms, though perhaps including variable leg spacing and though effective for trimming the leads projecting through such holes, have tended either to force the inserted leads back through the holes to some extent or unduly displaced the board itself so that the component after mounting was inadequately secured or became loosened with time and hence improperly electrically connected.
In the prior art, cut-clinch means have hitherto provided circuitry including an inserter for sensing the proper insertion of leads to be clinched when they have been detected as simply projecting from their lead holes. That arrangement is of course inadequate or ineffective for controlling inserting cycles when the printed circuit board holes are through-plated since inserting means being difficult to insulate, the plating completes the electric circuit between the inserting mechanism and the cut-clinch means and thus would prematurely return an inserting member. Moreover, in other respects such as the lack of capability for changing the length of a lead to be clinched or the angle to be defined by the clinched lead and the circuit board, the prior art arrangements have not been fully satisfactory. Such inadequacies and lack of versatility are overcome in the novel circuit and other arrangements herein proposed.